Fan

ABSTRACT

A fan includes a fan frame having an upright barrel, a fan blade unit having a fan hub with radial blades, and a driving module formed of a stator, an axle bearing, a core shaft and a rotor for causing rotation of the fan hub with the blades relative to the stator. The stator has a collar affixed to the barrel of the fan frame, radial ribs extending from and spaced around the periphery of the collar, and three-dimensional wings respectively connected to the free ends of the radial ribs each three-dimensional wings having a smoothly arched and radially and axially extending outer surface.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a fan and more specifically, to a highperformance fan in which the stator of the driving module is made out ofa magnetic powder material and has three-dimensional wings to provide athree-dimensional magnetic path.

2. Description of the Related Art

Following fast development of computer technology, high-speed CPUs(Central Processing Units) have been continuously created. Thesehigh-speed CPUs produce much heat during operation. In order to maintainnormal operation of a CPU, heat must be quickly carried away from theCPU. Cooler modules are developed for this purpose. A conventionalcooler module is known comprising a heat sink and a cooling fan. Theheat sink is attached to the CPU of a computer system to absorb heatenergy from the CPU and to transfer absorbed heat energy to itsradiation fins. The cooling fan is attached to the radiation fins andcontrolled to cause currents of air toward the radiation fins, therebydissipating heat from the radiation fins into outside open air.

A cooling fan for cooler module is generally comprised of a support, afan motor mounted in the support, and a fan blade assembly coupled tothe fan motor and rotatable by the fan motor. When an electric currentis connected to the windings at the stator of the motor, the rotor ofthe fan motor is caused to rotate relative to the stator, and thereforethe fan blade assembly that is affixed to the rotor is rotated to causecurrents of air. The stator is comprised of a stack of silicon steelplates, providing a two-dimensional magnetic path. This two-dimensionalmagnetic path design leads to a severe magnetic leakage. Further,because the component parts of the motor must be mounted inside the fanhub, the design of the motor is limited to the configuration of the fanhub, and the fan hub must have a certain dimension. Because the fan huboccupies much installation space in the casing of the cooling module,the blades are relatively shortened, resulting in a reduced windcapacity. When a downward blowing type cooling module is installed todissipate heat from a CPU, the hottest area of the heat sink is at thecenter area of the radiation fins right below the cooling fan. However,because the fan hub has a certain dimension and is disposed right abovethe hottest center area of the radiation fins, currents of air are notbe directly sent toward the hottest center area of the radiation fins,resulting in low performance of the cooler module. When increasing thespeed of the cooling fan to increase the wind capacity, the noise levelof the cooling fan will be relatively increased. Adding a thermal pipecan enhance the heat dissipation performance of the cooler module.However, the use of a thermal pipe relatively increases the cost of thecooler module.

The fan hub size is limited by the stator size of the motor. Further,the magnetic loss of a silicon steel plate is indirectly proportional toits silicon content. The magnetic loss of a silicon steel plate reachesthe lowest level when its silicon content is at about 6 wt %˜6.5 wt %.However, increasing the silicon content of a silicon steel platerelatively increasing its fragility level. It is difficult to stamp asilicon steel plate having a high fragility level into a thin sheet, sothe silicon content of regular silicon steel plates is controlled below3 wt %. In addition, the magnetic loss will reduce 5˜10 times whensilicon steel plates having silicon content 3˜6.5 wt %. Therefore, usinga material of low magnetic loss level for the stator of a motor caneffectively lower the voltage and energy loss of the motor.

To a fan motor, it is quite important by using a material of lowmagnetic loss level to maintain the magnetic properties. Enhancing themagnetic properties of the stator of a fan motor can obtain a relativelygreater torsional force under the same working voltage. In addition, tochange the design of motor by using a three dimensional magnetic pathalso can effectively increase the air gap flux density to improve thetorsional force. Therefore, the stator size of fan motor can be smallerand relatively reduces the length of the enameled wire to lower thetemperature level resulted from copper loss. Reducing the stator size offan motor can also reduce the size of the fan hub, so that the length ofthe fan blades can be relatively increased to improve the wind capacityand the heat dissipation efficiency of the cooler module.

SUMMARY OF THE INVENTION

The present invention has been accomplished under the circumstances inview. According to one aspect of the present invention, the fan iscomprised of a fan frame, a fan blade unit and a driving module. The fanframe comprises a base and a barrel perpendicularly extending from thebase. The driving module is comprised of a stator, an axle bearing, acore shaft and a rotor. The fan blade unit comprises a fan hub and aplurality of radial blades connected to and equiangularly spaced aroundthe fan hub. According to another aspect of the present invention, thestator comprises a collar sleeved onto the barrel of the fan frame andaffixed thereof, a plurality of radial ribs radially extended from andequiangularly spaced around the collar for the winding of a respectivewinding, and a plurality of three-dimensional wings at the free end ofeach radial rib. The three-dimensional wing each has a smoothly archedsurface radially and axially extending at an outer side. According tostill another aspect of the present invention, the stator is made out ofa magnetic powder material, providing a three-dimensional magnetic path.Based on the isotropic characteristics of the magnetic powder materialto combine with the three-dimensional magnetic path type motor design,the invention establishes a streamlined fan hub shape, reduces the fanhub size, extends the length of fan blades, and improves the performanceand torsional force of the driving module, thereby increasing the windcapacity of the fan. When compared to conventional fan designs, a fanmade according to the present invention has a relatively lower noiselevel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic sectional side view of a fan in accordance withthe present invention.

FIG. 2 is an elevational view of the stator for the driving module ofthe fan in accordance with the present invention.

FIG. 3 is a schematic drawing showing the three-dimensional magneticpath of the stator for the driving module of the fan in accordance withthe present invention.

FIG. 4 is an elevational view of the stator in accordance with a firstembodiment of the present invention.

FIG. 5 is an elevational view of the stator in accordance with a secondembodiment of the present invention.

FIG. 6 is an elevational view of the stator in accordance with a thirdembodiment of the present invention.

FIG. 7 is an elevational view of the stator in accordance with a fourthembodiment of the present invention.

FIG. 8 is a sectional side view of FIG. 7.

FIG. 9 is an elevational assembly view of the fan in accordance with thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 1, 2 and 9, a fan 2 in accordance with the presentinvention is shown comprised of a fan frame, a driving module and a fanblade unit. The driving module is comprised of a stator 1, at least oneaxle bearing 143, a core shaft 22 and at least one rotor 23. The fanframe comprises a base 14 and a barrel 141 perpendicularly extendingfrom the center of one side of the base 14. The fan blade unit iscomprised of a fan hub 21 and a plurality of blades 24 radiallyconnected to the fan hub 21. The fan frame secures the fan blade unitand the driving module.

The stator 1 comprises a collar 11, a plurality of three-dimensionalwings 13 equiangularly spaced around the collar 11, and a plurality ofradial ribs 12 equiangularly spaced around the collar 11 and radiallyconnected between the periphery of the collar 11 and thethree-dimensional wings 13. Windings 121 can be directly wound round theradial ribs 12. Unlike a conventional design to set plastic pads on thetop and bottom sides of the motor stator before winding of the enameledwire on silicon steel plates, the invention greatly reduces the lengthof the enameled wire, lowering copper loss and improving motorperformance. By means of inserting the barrel 141 through the collar 11,the stator 1 is supported on the base 14 of the fan frame (see FIG. 1).The barrel 141 defines therein an axially extending axle bearing hole142. The axle bearing 143 is mounted in the axle bearing hole 142 insidethe barrel 141.

The fan hub 21 can be shaped like a flat cup. Alternatively, the fan hub21 can be nose-shaped. The core shaft 22 is perpendicularly affixed tothe center of the inner side of the fan hub 21 and mounted in the axlebearing 143 to support the fan blade unit on the fan frame. The rotor 23is affixed to the inside of the fan hub 21. The blades 24 are affixed tothe outside of the fan hub 21.

During installation, the collar 11 is sleeved onto the barrel 141 abovethe base 14, and then the axle bearing 143 is mounted in the barrel 141,and then the core shaft 22 is affixed to the fan hub 21 and mounted inthe axle bearing 143 to support the fan blade unit on the fan frame,allowing rotation of the core shaft 22 with the fan blade unit in theaxle bearing 143. Further, before installation of the collar 11, thewindings 121 are wound round the radial ribs 12. When an electriccurrent is applied to the windings 121, the collar 11 define with theradial ribs 12 and the wings 13 a three-dimensional magnetic path forenabling the windings 121 to induce with the rotor 23, thereby causing amagnetic repulsive force to rotate the rotor 23 relative to the stator1, and therefore the fan blade unit is rotated with the rotor 23 and thecore shaft 22 relative to the stator 1 and the fan frame.

The collar 11, the radial ribs 12 and the wings 13 of the stator 1 aremade in integrity by means of powder metallurgy, mechanical processingor casting. Alternatively, The collar 11, the radial ribs 12 and thewings 13 can be separately made, and then fastened together by a bondingtechnique, welding technique, riveting, screw joint or plug joint.Further, by means of the three-dimensional magnetic path design of thestator 1, different magnetic materials may be selectively used todetermine the magnetic characteristic of the stator 1, thereby improvingthe speed when the rotor 23 is caused to rotate by the stator 1, andtherefore the driving efficiency and torsional force of the drivingmodule can be greatly improved. The magnetic materials can be softmagnetic metal materials (Fe, Ni, Si, Co, etc.) or ferromagneticmaterials (MO—Fe₂0₃, MO-6Fe₂0₃, MM '0₃, etc.). Further, by means of thecollar 11, the stator 1 is directly coupled to the axle bearing 143.

Further, the radial ribs 12 of the stator 1 can be made in the shape ofa straight bar or cross, or having a star-shaped cross section. Theradial ribs 12 can also be made having a solid structure, and steppedconfiguration. Further, the collar 11 of the stator 1 can be formedintegral with the barrel 141 of the fan frame.

Further, the wings 13 are based on a three-dimensional design. The outersurface of each wing 13 is a curved surface that curves smoothly inaxial direction as well as radial direction. The rotor 23 is a magnetthat can be shaped like a hollow cylinder. Alternatively, the rotor 23can be made having a curved inner surface that fits the curvature of thecurved outer surface of each wing 13. The fan hub 21 can be shaped likea flat cup. Alternatively, the fan hub 21 can be nose-shaped to reducethe dimension so that the blades 24 can be made relatively longer toprovide a relatively greater wind capacity for enabling outside coolingair to be directly guided into the hottest center area right beneath thefan hub 21 to enhance the heat dissipation efficiency. Therefore, undera same heat dissipation efficiency, the speed of the fan 2 can berelatively reduced, lowering the noise level and the power consumption.

FIGS. 3A and 3B illustrate the three-dimensional magnetic path of thestator of the driving module. FIG. 3A shows co-existence of fourmagnetic flux loops during rotation of the rotor. For instance, magneticflux flows from the rotor 23 toward one wing 13, and then flows radiallyfrom the wing 13 to the associating radial rib 12, and then flows fromthe radial rib 12 to the collar 11, and then flows along the peripheryof the collar 11 to another radial rib 12, and then flows back to thewing 13 and then the rotor 23, forming one magnetic flux loop.Therefore, two magnetic paths are bilaterally extending over one radialrib 12, and the two magnetic paths at each radial rib 12 extend inreversed directions along the collar 11 toward another two radial ribs12 for further circulation. FIG. 3B illustrates the magnetic path at oneside of one wing. The magnetic flux flows from the rotor 23 toward thewing 13 and then the associating radial rib 12. Because the surface areaof the wing 13 is greater than the lateral area of the stacked siliconsteel plates in a conventional fan structure, much magnetic flux isallowed to pass, thereby improving the performance of the motor.

The shape of the stator 1 shown in FIG. 2 is obtained subject to acomputer digital simulation to calculate the three-dimensional magneticpath and the motor performance. This model has been examined by means ofa test, and the test result shows that the diameter of the silicon steelplates of the motor can be reduced from the original design of 24 mm to21.6 mm, i.e., the motor diameter can be reduced by 10%; the fan hubdiameter can be reduced from the original design of 32.77 mm to 29.35mm; the fan speed can be increased from the original design of 2500 rpmto 3000 rpm. Therefore, the invention greatly reduces the profile of thedriving device, and increases the size of the blades to increase thewind capacity.

FIG. 4 is an elevational view of the stator in accordance with the firstembodiment of the present invention. The stator 1 may be variouslyshaped. FIG. 5 is an elevational view of a stator for fan in accordancewith a second embodiment of the present invention. FIG. 6 is anelevational view of a stator for fan in accordance with a thirdembodiment of the present invention. FIG. 7 is an elevational view of astator for fan in accordance with a fourth embodiment of the presentinvention. FIG. 8 is a sectional side view of the stator in accordancewith the fourth embodiment of the present invention. According to thefirst embodiment of the present invention, each wing 13 of the stator 1has a smoothly arched outer surface, and each radial rib 12 extendsperpendicular from the flat inner surface of the associating wing 13(see FIG. 4). According to the second embodiment of the presentinvention, the wings 13 have a transverse width relatively greater thanthe transverse width of the radial ribs 12 (see FIG. 5). According tothe first and second embodiments of the present invention, the upperpart of each wing 13 above the elevation of the associating radial rib12 has a vertical height greater than the vertical height of the lowerpart of each wing 13 below the elevation of the associating radial rib12 (see FIGS. 4 and 5). According to the third and fourth embodiments ofthe present invention, each wing 13 has a transverse width relativelylonger than its vertical height (see FIGS. 6 and 7). According to thefourth embodiment of the present invention, each wing 13 has its bottomside smoothly curved downwardly inwards and suspending below theelevation of the associating radial rid 12 (see FIG. 8).

Further, the fan frame can be made having a part assembled to connectwith a circuit board to form a fan control circuit, facilitating massproduction.

In conclusion, the invention provides a fan 2 comprised of a fan frame,which comprises a base 14 and a barrel 141 perpendicularly extendingfrom the center of the base 14, a driving module, which comprises astator 1, at least one axle bearing 143, a core shaft 22 and at leastone rotor 23, and a fan blade unit, which comprises a fan hub 21 and aplurality of blades 24 radially connected to the fan hub 21. The stator1 has a three-dimensional profile. By means of utilizing the isotropiccharacteristics of a magnetic powder material to combine with athree-dimensional magnetic path type motor design, the inventionestablishes a streamlined fan hub shape, reduces the fan hub size,extends the length of fan blades, and improves the performance andtorsional force of the driving module, thereby increasing the windcapacity of the fan; i.e., by means of the three-dimensional design ofthe wings 13 of the stator 1 and the smoothly arched profile of the fanhub 21 and the rotor 23, the invention greatly reduces the dimension ofthe driving module and the size of the fan 2 and extends the length ofthe blades 24.

By means of the three-dimensional design of the stator 1 to control themagnetic path, the invention greatly improves the speed and torsionalforce of the driving module (motor).

In actual practice, the fan 2 of the present invention has the followingfeatures and advantages:

1. The stator 1 is made out of a magnetic material defining athree-dimensional magnetic path, eliminating magnetic leakage andimproving the speed and torsional force of the driving module (motor).

2. Based on the three dimensional design of the wings 13 and radial ribs12 of the stator 1, the size of the fan hub 21 can be relativelyreduced, and the length of the fan blades 24 can be relatively increasedto increase the wind capacity of the fan 2.

3. The fan hub 21 matches the smoothly arched shape design of the stator1 so that outside cooling air is effectively guided to the hot source atthe center below the fan hub 21, enhancing the heat dissipatingperformance.

Although particular embodiments of the invention have been described indetail for purposes of illustration, various modifications andenhancements may be made without departing from the spirit and scope ofthe invention. Accordingly, the invention is not to be limited except asby the appended claims.

1. A fan comprising: a fan frame, said fan frame comprising a base and abarrel perpendicularly extending from the center of said base; a fanblade unit, said fan blade unit comprising a fan hub and a plurality ofblades radially connected to said fan hub; a driving module, saiddriving module comprising a stator affixed to said barrel of said fanframe, said stator comprising a collar sleeved onto said barrel of saidfan frame and a plurality of radial ribs radially extending from andequiangularly spaced around the periphery of said collar for the windingof a respective winding, at least one axle bearing mounted inside saidbarrel of said fan frame, a core shaft affixed to said fan hub of saidfan blade unit and supported in said at least one axle bearing, and atleast one rotor affixed to an inner side of said fan hub and spacedaround said stator; wherein said stator comprises a plurality ofthree-dimensional wings respectively connected to the free ends of saidradial ribs remote from said collar, said three-dimensional wings eachhaving a smoothly arched surface radially and axially extending at anouter side.
 2. The fan as claimed in claim 1, wherein said stator ismade out of a magnetic material to provide a three-dimensional magneticpath, said magnetic material being elected from one of the soft magneticmetal materials including Fe, Ni, Si and Co and the ferromagneticmaterials including MO—Fe₂0₃, MO-6Fe₂0₃ and MM '0₃.
 3. The fan asclaimed in claim 1, wherein said radial ribs of said stator have theshape of a straight bar.
 4. The fan as claimed in claim 1, wherein saidradial ribs of said stator have the shape of a cross.
 5. The fan asclaimed in claim 1, wherein said radial ribs of said stator have astar-shaped cross section.
 6. The fan as claimed in claim 1, whereinsaid fan hub is shaped like a flat cup, having a radially and axiallyextending smoothly curved outer surface.
 7. The fan as claimed in claim1, wherein said fan hub has a nose-like shape and a radially and axiallyextending smoothly curved outer surface.
 8. The fan as claimed in claim1, wherein said radial ribs of said stator are solid prism having astepped cross section.
 9. The fan as claimed in claim 1, wherein saidstator is made in integrity by means of one of the techniques of powdermetallurgy, mechanical processing and casting.
 10. The fan as claimed inclaim 1, wherein said collar, said radial ribs and said wings of saidstator are separately made and fastened together by means of one ofbonding technique, welding technique, riveting, screw joint and plugjoint
 11. The fan as claimed in claim 1, wherein said wings of saidstator each have a smoothly arched surface which is composed bydifferent flat surface, curve surface, arched surface and cylindricalsurface.
 12. The fan as claimed in claim 1, wherein said rotor is formedof an annular magnet, said annular magnet having an inner surfacefitting the curvature of the wings of said stator.
 13. The fan asclaimed in claim 1, wherein said barrel in the center of said fan frameis assembled with a hollow part which is assembled with said stator atthe hollow part outside and the bottom of hollow part to connect with acircuit board to form a fan control circuit.
 14. The fan as claimed inclaim 1, wherein said collar inside of said stator is formed integralwith the bearing where the bearing assembled in the center of said fanframe to displace said barrel.